A scene in a major new film starring Harrison Ford and Sean Penn in which an Iranian character murders his sister in a so-called "honour killing" has been changed after complaints.

Crossing Over is a Los Angeles-set, race-themed drama backed by film moguls Harvey and Bob Weinstein which also stars Ashley Judd and Ray Liotta. It would appear to focus on similar themes to Paul Haggis' Oscar-winning Crash, from 2004.

The Weinstein Brothers have courted controversy throughout their careers and were back in familiar territory after an actor of Iranian descent not on the project but who read the screenplay took umbrage over the scene, in which an Iranian-American man kills his sister after discovering she has been having an affair with a Latino man.

The actor complained to the National Iranian American Council (NIAC), which promptly labelled the scene unrealistic and inflammatory and approached director Wayne Kramer and an actor during the shoot to demand changes.

Changes were made following an ongoing discussion between the filmmakers and NIAC members. The Weinsteins have not revealed which actor was approached on set and would not discuss the revised screenplay.

"Honour killings are accepted in some Middle Eastern cultures but not accepted in Iranian culture," NIAC president Trita Parsi said. "They sometimes happen in remote areas of Iran, but there are no cases of Iranians doing this in the US."

"While we believe strongly in freedom of expression, we also believe in the importance of constructive dialogue between artists and the communities they seek to portray," a Weinstein Company spokeswoman said. Crossing Over opens in the US later in the year.